Lift (elevator) movements to pump water 6

[Boiler1]

Hi Friends,

I've got request from an architect to investigate possibility of using the lift movements to pump the rain water from collection tank into the flushing water head tank located on the roof.

Can you help me with any ideas or refer to some source of info.

Also,

Can anybody recommend reliable Mechanical Costs & Men-Hours data approved by CIBSE (I suppose ASHRAE would also be OK for Men-Hours)

Thanks,

 

[MintJulep]

Well that is certainly a interesting request.

Does he actually mean to have the elevator cars carry water? Even without doing any research, I am fairly confident in stating that I don't think this has ever been done.

What is the vertical distance (head) from the sump to the roof tank?

Assuming that the goal is to actually have a tank built into the elevator car (or on the counter weight end of the cable), this seems like a bad idea because:

1. Water is heavy. The elevator system would need to be rated to lift a full passenger load plus the full water load. Initial costs would be higher, as well as maintenance costs.

2. You need to transfer the water from the sump to the elevator tank, then to the roof tank. This means you would need some sort of automatic coupling that could be relied upon not to leak. You might be able to get by with a gravity feed at the bottom, but it seels like you would need a transfer pump at the top (unless the eleveator goes above roof level).

3. The inertial effects of having water sloshing around is unlikely to make the elevator people happy.

4. Once a load of water is taken on, the elevator needs to go all the way to the roof to dump it. But not all elevator trips need to go to the roof. This means you need to either divert the elvator from passenger service to pump service, or pay to carry water up and down the building until a trip to the roof can be made.

5. Even if you are going to carry water only during unoccupied periods, the cost to maintain and operate an elevator has just got to be way more than the cost to maintain a standard pump.

6. What happens if there is a catastrophic failure of the elevator tank while the elevator is moving?

 

[btrueblood]

Or think about it another way: would it make sense to connect a pump to the elevator drive motor? If the answer to that question is no, then why would any other way of making the elevator prime mover move the water make sense?

 

[friartuck]

Hi Boiler 1

just a point that you might find interesting. There are a number of water driven lifts in the UK. I think theres one at Scarborough and another at Lynton North Devon. They work in pairs and have a tank fitted underneath.

The top lift fills with water and falls by the weight, lifting the lighter lift up. When the heavy lift reaches the ground level, it dumps its water and is lifted by the other lift which has had its tank filled with water.

They have been in use since Victorian times.

The request to lift water by using the lift I feel is a bit of a 'one off' and is not economically feasible. I agree with MintJulep. Don't waste too much time or effort on this one. Buy a pump, it's miles cheaper.

Friar Tuck of Sherwood

 

[Skogsgurra]

It is good to see that common sense still outweighs fantastery. Stars to you all.

 

[ClydeMule]

What if you used the weight of the falling car as your pump driver?

Let's say a second shaft was installed parallel to the main shaft. The second shaft would just act like a large piston pump.

You of course could not pump water at a constant rate, but the you would be burning up the braking energy in a more useful way.

Except...

Good luck finding an elevator company to service it. Buy a pump.

Clyde

 

[MintJulep]

Clyde,

It is possible to capture the elevator motor's braking energy and use it to drive a pump. Rengenerative braking is fairly common on elevators.

The availability of the power would likely be too sporadic to be the sole driver for a pump.

 

[Boiler1]

Thanks all,

I have contacted few lift manufacturers in the meantime(IRL & UK) & none of them have ever come across anything similar in practice.

It's probably the best to buy a pump after all, but for the sake of good business relations you have to spend some time investigating even unreasonable requests.

My initial taughts were, however, closest to Clydemule's idea - parallel piston shaft.

Friartuck - thanks for the info. Must se that next time in Scarborough.

Thank you all again & if anybody has any info on men-hours, I would appreciate it

 

[jherbert]

hi,

- where is the collection cistern ground/basement/upper floor level? or what is the required head?

- what type of lift is envisaged? (hydraulic - no chance)


If you have a traction type lift I'd drive a small self-priming pump, driven from the lift motor/pully.

Just because it has not been done before doesn't make wrong. As others have mentioned the lift manufacturer would need to be involved. Shame it was an architect's idea.

cheers,

 

[chicopee]

WHY NOT COLLECT RAIN WATER AT ROOF LEVEL TO FILL ROOF MOUNTED TANK--A MUCH SIMPLER AND LEAST COSTLY METHOD THAN ADAPTING A SYSTEM RIGGED TO ELEVATOR MOVEMENT. IF ARCHITECT STILL INSIST THAN DYNAMIC BREAKING (REGENERATIVE POWER BY ONE OF THE ABOVE RESPONDERS) IS THE WAY TO GO IF THERE IS ENOUGH POWER GENERATED AND POSSIBLY STORED.